The Case of $α_s$: $Z$ versus Low Energies, or How Nature Prompts us of New Physics

Abstract

The values of $α_s$ determined from low- and high-energy measurements are in irreconcilable contradiction with each other. The current status of the problem is critically reviewed. Consequences of the $α_s$ contradiction, in conjunction with other anomalies detected at the $Z$ peak, are discussed. The write-up is updated in accordance with experimental numbers reported at summer conferences.